Transmission system.



I). D. MILLER.

TRANSMISSION SYSTEM.

APPLICATION FILED OCT. 4, 19713.

Patented May 12, 1914.

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UNITED STATES, PATENT orricn DANIEL D. MILLER, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COMPANY, OF NEW YORK, N. Y., A CORPDRATION OF ILLINOIS.

TRANSMISSION SYSTEM.

Specification of Letters Patent.

Patented May 12, 1%)14.

To all whom it may concern Be it known that I, DANIEL D. h IILLER, a citizen of the United States, residing at New York city, in the county and State of New York, have invented a certain new and useful Improvement in Transmission Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to the transmission of electrical energy and more particularly to a transmission system in which a plurah ity of electro-responsive devices connected with a transmission line may be operated from a source of current located at either end of the line.

The object of the invention is to provide means for automatically tapering the resistance of the line so that all of the electroresponsive devices along the line will receive approximately the same amount of current regardless of which of the two sources of operating current is used.

In accordance with this invention, means are associated with each of the electro-responsive devices operating automatically in response to the operating current to vary the resistance in circuit with the electroresponsive devices in accordance with the distance of these devices from the source of operating current.

The drawing illustrates this invention as applied to a selective signaling scheme of the class in which step by step selective signaling devices located at various points along a transmission line are operated by means of current impulses from a source of energy at a sending or calling station to close a circuit for one signal.

As shown in said drawing, A and B designate sending or calling stations located at opposite ends of a metallic line embraclng line wires 5 and 6, between the ends of which are connected way stations C and D. Located at each of the sending stations A and B is an impulse transmitting apparatus comprising an impulse transmitter wheel 10' in a local circuit with a relay 11 and a bat tery 12. The operation of the transmitter wheel 10 operates the relay 11 to close and open contacts 13 and i l for connectlng a source of current .15 with the line wires 5 and 6. There may be a transmitter wheel 10 for each selector on the line.

Located at each of the way stations C and D is a selective apparatus comprising a step by step element 18 moved under the control of fast and slow acting magnets 19 and 20 and stepping and holding pawls 21 and 22 to close contacts 23 and 2st for completing a circuit through a signal magnet 25. As shown in the drawing, the stepping and holding magnets 19 and 20 are connected in series and in bridge of the line wires 5 and 6. Also connected in this bridge is the winding 30 of a polarized relay and a variable resistance unit 31. An armature 32 for said polarized relay is adapted in its alternate positions to cut in or short-circuit winding of the variable resistance 31 by the opening or closure of a contact 35. In the drawing the shunt circuit for this variable resistance is shown as open at way station C and closed at way station D. This is the condition which will prevail when the way stations are being called from station A. When calling from station B this condition will be reversed, that is, the shunt circuit will be opened at way station D and closed at way station C. The positions of the armatures of these polarized relays are determined by the direction of currents over the line wires and as shown the calling currents are sent over the line wires in opposite directions by the calling devices at the opposite ends of the line.

Referring now to the operation of the system it will be assumed that the despatcher at the sending station A desires to call the party at way station C. He will accordingly start the transmitter wheel 10 to rotating which will operate the relay 11 to open and close the contacts 13 and l t to connect battery 15 with the line wires and 6 and disconnect it therefrom. The current impulses sent out by this operation will be in a direction to cause the polarized relay winding 30 to attract its armature 32 in a counterclockwise direction. This will open the contact at way station C and thus remove the short circuit from the variable resistance, while at the way station D the contact 35 will be clos d, thus shortcircuiting a portion of the resistance 31. This operation will automatically taper the line so that the bridge at the end farthest from the end of the line from which calling currents are emanating will receive approxi mately the same amount of current as that at the end nearest the source of calling current. In the drawing the full line position of the armature 32 of the polarized relay is the position which it assumes when the callin'g current is from the station A and the dotted line position is that which it assumes when the calling current is from the station B. It is obvious that when calling from station B, the armatures 32 will be moved in a clockwise direction to open the contact 35 at station D and close the contact 35 at the station C, thus reversing the line conditions and tapering the line resistance in the direction opposite to that resulting when calling current was from station A.

Retardation coils 36, 37 and 38 are connected in the line wires at each sending station and a condenser 39 is bridged across the line wires, the purpose being to graduate the impulses from the sending station in order that they will not cause a thump in a telephone receiver which may be connected with the line wires during calling.

In actual practice there will be a number of intermediate stations between the stations G and D and it is obvious that the resistances for each station may be calculated and so connected through the contacts of the polarized relay that the correct amount of resistance will be cut in or out at each station depending upon which end of the line calling current is applied.

hat I claim is:

1. In a transmission system, a transmission line, a plurality of electro-responsive devices connected with said line at separated points, a source of operating current located at each end of said line, and means for automatically tapering the resistance of said line to the calling current, whereby each of said electro-responsive devices will receive the same amount of current from either of said sources.

2. In a transmission system, a transmission line, a source of operating current at each end of said line, a plurality of electroresponsive devices connected with said line, resistances in circuit with each of said electro-responsive devices, and means also in circuit with each of said electro-responsive devices operating automatically upon the application of operating current to either end of said line to taper the line resistance to the source of current supplied.

3. In a transmission system, a transmission line, a source of operating current located at each end of said line, electro-responsive devices connected with said line at varying distances from the ends, resistances in series with each of said electro-responsive devices, polarized devices in circuit with each of said electro-responsive devices and means controlled byv said polarized devices operating to cut in or out resistance with the associated electro-responsive device upon the application of one of said sources of operating current to the end of the line with which it is associated.

4. In a transmission system, a transmission line, two sources of operating current of opposite polarity associated with the opposite ends of said line, electro-responsive devices connected with said line at varying distances from the sources of operating currents, a resistance connected in series with each of said lines, a polarized relay connected in circuit with each of said electro-responsive devices, and a shunt circuit for each resistance controlled by said polarized relay, said polarized relay operating to cut in or out resistance with its corresponding electro-responsive device depending upon its distance from the source of operating current applied to the line.

In witness whereof, I hereunto subscribe my name this 2d day of October A. D. 1913.

DANIEL D. MILLER.

Witnesses EDNA D. lVIAGURK, ANNA M. F ENNELL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

. Washington, D. C. 

